What causes a parasitic draw on a battery?

What causes a parasitic draw on a battery?

A parasitic battery drain is just something that consistently and continually drains your battery. This could be a faulty relay, a headlight/dome-light switch, alternator, or any other electrical gremlins. Taking your car to a mechanic with an “unknown” culprit can cost you big bucks as well.

What causes a car to draw power from the battery?

Learn more… If your vehicle is drawing power from the battery and all of the lights and other electrical components are off, you might have a parasitic battery drain (or draw). Luckily, you can usually find the cause of a parasitic draw yourself. Start by connecting a digital multimeter to the negative battery terminal of your vehicle.

How much power does a negative battery draw?

Touch a lead to the negative battery cable terminal. Touch the other lead to the negative battery post, completing the circuit within the multimeter, which will display the amp draw. Power draw should be under 50 milliamps. This will display as 0.05 amps.

Is there a way to drain a battery in one day?

That seems like a tiny amount, but a single incandescent dome light pulls enough power to drain a battery in one day. Remember that the drain doesn’t have to take your battery to zero overnight, just low enough for it to not start.

When to look for a parasitic battery drain?

A parasitic drain is when an electrical device is using battery power when the car is closed, and the ignition key removed. Therefore, when doing this test make sure that the dome light, under hood light, trunk light, etc. are off.

Learn more… If your vehicle is drawing power from the battery and all of the lights and other electrical components are off, you might have a parasitic battery drain (or draw). Luckily, you can usually find the cause of a parasitic draw yourself. Start by connecting a digital multimeter to the negative battery terminal of your vehicle.

Touch a lead to the negative battery cable terminal. Touch the other lead to the negative battery post, completing the circuit within the multimeter, which will display the amp draw. Power draw should be under 50 milliamps. This will display as 0.05 amps.

What should the parasitic draw be on a car battery?

For testing purposes, we will select 2A or 200mA in the amp section of the meter. This is where we can see the parasitic draw on the battery. The reading for a normal vehicle with no parasitic draw can range from 10mA to 50mA, depending on the manufacturer and the amount of computers and features the vehicle has.

That seems like a tiny amount, but a single incandescent dome light pulls enough power to drain a battery in one day. Remember that the drain doesn’t have to take your battery to zero overnight, just low enough for it to not start.